WO2009139664A1

WO2009139664A1 - Method for producing carbon dioxide chemical adsorbent

Info

Publication number: WO2009139664A1
Application number: PCT/RU2009/000214
Authority: WO
Inventors: Николай Федорович ГЛАДЫШЕВ; Тамара Викторовна ГЛАДЫШЕВА; Леонид Эдуардович КОЗАДАЕВ; Эдуард Ильич СИМАНЕНКОВ; Борис Викторович ПУТИН; Сергей Борисович ПУТИН; Марина Петровна АРХИПОВА; Анатолий Васильевич ТЯНИКОВ
Original assignee: Открытое Акционерное Общество "Корпорация "Росхимзащита"
Priority date: 2008-05-12
Filing date: 2009-05-05
Publication date: 2009-11-19
Also published as: UA100266C2; RU2381831C2

Abstract

The invention relates to methods for producing carbon dioxide chemical adsorbent which is based on hydroxides of alkali and/ or alkali-earth metals and can be used in means for protecting respiratory organs. The method for producing carbon dioxide chemical adsorbent for respiratory systems involves combining alkali and/ or alkali-earth metal hydroxides with a fibrous material, shaping adsorbent in the form of a sheet and drying it. The alkali and/or alkali-earth metal hydroxides are used in the form of an aqueous dispersion and the alkali and/ or alkali-earth metal hydroxides is combined with the fibrous material by accommodating the aqueous dispersion between the layers of a porous fibrous material. The alkali and/or alkali-earth metal hydroxides such as potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and the similar hydroxides chemically active to carbon dioxide can be used as metal hydroxides. The aqueous dispersion can be of a paste or suspension consistency or in the form of a solution. The following materials can be used as a porous fibrous material: fibre paper, glass-fiber mat, heat resistant non-flammable materials such as Nomex, Kevlar (Du Pont, USA), Rusar and Arselon (Russia) and any other alkali-proof low specific density materials. The invention makes it possible to increase by 20-40% the reaction capacity of the adsorbent, thereby extending the possibilities of using it in systems for removing carbon dioxide from air, the adsorbent production method being technologically simple.

Description

METHOD FOR PRODUCING CHEMICAL CARBON DIOXIDE ADSORBENT

Technical field

The invention relates to methods for producing a carbon dioxide adsorbent based on alkali and / or alkaline earth metal hydroxides, intended for use in respiratory protective equipment.

State of the art

A known method of manufacturing a carbon dioxide adsorbent based on alkali and alkaline earth metal hydroxides for respiratory systems (US patent Xs 7329307, IPC BOlD 53/02, 2008, US patent JV ° 7326280, IPC BOlD 53/02, 2008), by which the mixture is extruded powders of metal hydroxide, in particular anhydrous lithium hydroxide, and polyethylene with the addition of a lubricant (mineral oil) to form a sheet. A heated die may be used to extrude the material into a flat sheet. The extruded material can be pressed between two calender rolls, one of which is smooth, and the second is provided with grooves, due to which protrusions are formed on the sheet of material. The sheet acquires a ribbed shape, which ensures the creation of the necessary channels for the gas flow during the operation of the absorber.

The ribbed sheet can be cooled to a temperature below the melting point of polyethylene and then wound into a roll. One example of an extruded composition includes (in% by mass): lithium hydroxide 65.3; grease 33; polyethylene 1.7.

Next, the extraction process is carried out in order to remove grease in the roll. To do this, the rolls are saturated with hexane, then heated and dried in vacuum until the hexane is completely removed. After cooling, the rolls are stored at ambient temperature in an atmosphere free of carbon dioxide.

To effectively remove carbon dioxide, the adsorbent is hydrated before use. The hydration of the ribbed sheets is carried out by uniformly applying liquid water to the surface of the sheet.

However, this method of manufacturing a CO ₂ adsorbent is technologically complex and involves many stages: mixing the starting components of the powders of anhydrous lithium hydroxide and polyethylene with the addition of a lubricant, extrusion of the resulting mixture, removal of the organic component by extraction of the obtained adsorbent with hexane, followed by its evaporation by heat treatment in vacuum and hydration of the anhydrous adsorbent.

A method of manufacturing an adsorbent is limited by the use of low-performance vacuum treatment, and the operation of moistening the adsorbent does not provide a uniform distribution of moisture throughout the volume of the sheet adsorbent, which negatively affects the sorption activity of the adsorbent to carbon dioxide.

The use of organic polymer material reduces the gas permeability of the adsorbent and the access of carbon dioxide to the active component - lithium hydroxide.

A known method of manufacturing a carbon dioxide absorber based on alkali and alkaline earth metal hydroxides for respiratory systems (US patent JNa 5964221, NKI 128 / 205.12, 1999), according to which carbon dioxide adsorbent powder, in particular Sodasorb, manufactured by W.R. Grace and Co. and consisting of a mixture of calcium hydroxide, sodium hydroxide and potassium hydroxide, is mixed with a polymer powder, in particular high molecular weight polyethylene. The mixture is carried out in an extruder, while a lubricant (mineral oil) is injected into the mixture. Mixing is carried out with heating, while the polymer dissolves in the lubricant, which ensures uniform mixing of the polymer with the adsorbent. The resulting mixture is extruded into a composite sheet or other form. If necessary, the sheet is calendared, passing it between two rolls. After cooling of the sheet, the lubricant is removed by treating the sheet with a solvent, in particular hexane, after which the solvent is removed by blowing with dry nitrogen. Additionally, a polymer shrink operation is performed.

The obtained sheets of carbon dioxide absorber are rolled up and installed in the form of a cartridge in the cartridge of the respiratory system, while the sheets can be placed between permeable membranes. It is also possible to die cast this material with any given contour, for example in the form of ribs on a sheet. All options for the design of the sheet of absorbent material have a hydrophobic surface. The content of the required amount of moisture is provided by applying a water-alcohol mixture.

However, this method of manufacturing a CO ₂ adsorbent is also technologically complex. All the disadvantages of the above method should be to include additional operations of heat shrinkage of the adsorbent and purging with dry nitrogen, which significantly increases the cost of manufacturing the adsorbent and reduces its quality.

Closest to the claimed is a method of manufacturing a carbon dioxide absorber based on alkali and alkaline earth metal hydroxides for respiratory systems (US patent JNs 5165399, NKI 128 / 205.12, 1992), in which the carbon dioxide adsorbent based on alkali and / or alkaline earth metal hydroxides is combined with fibrous material by mixing the powdered adsorbent with the fibrous material, for example, in a high-speed mixer and the mixture is formed into a sheet. For molding, the mixture is dispersed into a liquid, which is any liquid that does not dissolve the adsorbent and fibrous material, and the resulting dispersion is cast in the form of a sheet in the usual way of making paper. The sheet is dried.

To increase the strength of the adsorbent, the sheet is placed between two layers of a membrane or permeable fabric and the resulting layers are combined in the form of a “sandwich”, for example, by ultrasound or by the method of piercing or needle-punched bonding of multilayer material used in the technology of producing nonwoven materials.

The resulting sheets are arranged accordingly for use in the respiratory system.

Alternatively, the mixture of fibrous material and metal hydroxide can be granulated. Granules may be included in the structure of the sheet in a dry manner. For example, a granular adsorbent is distributed between two sheets of a permeable membrane and they are joined by needle-punched method.

The membrane or tissue may be arranged with the adsorbent before or after the formation of the sheet (plate). In this case, the mixture of components dispersed in an appropriate solvent is poured onto a layer of permeable fabric such as, for example, Nomeh, using a papermaking technique. The sheet is dried and a second sheet of permeable fabric is applied on top. The two-layer structure is machined, for example, on needle-punched machines.

However, this method does not allow to obtain an adsorbent with sufficient reactivity to carbon dioxide, because, firstly, the polymer encapsulates particles of the active component of the adsorbent, which reduces it reactivity to carbon dioxide.

Secondly, the processing of the adsorbent on needle-punched machines violates and compacts its structure, reduces the porosity of the layer, and, consequently, the gas permeability of the adsorbent, which as a result reduces the reactivity to carbon dioxide.

Thirdly, the use of hydrophobic materials in the manufacturing process of the adsorbent leads to a decrease in the water content of the adsorbent and, accordingly, to a decrease in reactivity.

In addition, this method is periodic and technologically complex. The limiting stages of the technological process are dispersion of the mixture into a liquid and separation of the solid phase. Moreover, the use of organic components in the known method poses a threat of toxic impurities being released into the gas-air mixture during operation of the breathing apparatus by the user.

Disclosure of invention

The objective of the invention is to provide a method that allows to obtain improved operating characteristics of the adsorbent, resulting in increased reactivity of the adsorbent to carbon dioxide.

An additional result is to simplify the manufacturing technology of the carbon dioxide adsorbent.

This problem is solved by the fact that in the method of manufacturing a carbon dioxide adsorbent for respiratory systems, comprising combining alkali and / or alkaline earth metal hydroxides with fibrous material, sheet forming the adsorbent and drying, alkali and / or alkaline earth metal hydroxides are used in the form of an aqueous dispersion, and the combination of alkali and / or alkaline earth metal hydroxides with the fibrous material is carried out by placing an aqueous dispersion between the layers of the fibrous material.

The formation of the absorbent in the form of a sheet is carried out by rolling between waikami.

As the fibrous material, a porous fibrous woven or non-woven alkali-resistant material with a low specific gravity is used.

The aqueous dispersion is used as a paste, as a suspension, or as a solution.

The use of hydroxides in the form of an aqueous dispersion placed between layers of fibrous material, ensures that, during subsequent sheet formation, the pores of the fibrous material are completely and uniformly filled with the active component of the adsorbent (metal hydroxide), which makes it possible to create a uniform thickness of the adsorbent layer in the form of a sheet, and the absence of a polymer binder allows for high gas permeability of the adsorbent sheet, which ultimately leads to an increase in the rate of absorption of carbon dioxide by increasing the contact surface of the adsorbent with carbon dioxide and the elimination of entrainment and moisture from the adsorbent.

The fibrous material has the function of a reinforcing component and provides an adsorbent structure with a certain mechanical strength.

The absence of a polymeric binder in the composition of the adsorbent completely excludes the possibility of introducing any harmful impurities into the cleaned air. This eliminates the multi-stage process and ensures its continuity.

Embodiments of the invention

A method of producing an adsorbent is as follows.

The starting components are alkali and / or alkaline earth metal hydroxide mixed with water until an aqueous dispersion forms, which may have the consistency of a paste or suspension, or may be in the form of a solution. The aqueous dispersion is applied to a layer of porous fibrous material (woven or non-woven), which can be used any materials, for example, glass paper, glass mat, heat-resistant non-combustible materials such as Nomekh, Kevlar (Du Ropt, USA), Rusar, Arselon (Russia) or any other alkali-resistant materials with low specific gravity.

As metal hydroxides, alkali and / or alkaline earth metal hydroxides such as potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and others having chemical activity to carbon dioxide can be used.

A second layer of porous fibrous material is applied to the layer of fibrous material obtained at the previous stage, and the resulting structure (composition) is formed into a sheet in the usual way, for example, by rolling rollers.

The resulting adsorbent sheet is dried in the usual way, for example, b in a laboratory or industrial control cabinet with air ventilation. In this case, the drying parameters are set depending on the specified residual moisture content in the adsorbent.

Next, the sheets of adsorbent, depending on the purpose, are rolled up and placed in a cartridge, thereby obtaining a rechargeable cartridge for cleaning the exhaled air of carbon dioxide for an individual use device, or the adsorbent is used in the form of manufactured sheets, placed in the appropriate device (device, design ) in closed air purification systems.

Example 1

An aqueous dispersion is prepared, for which 7.5 g of potassium hydroxide KOH is dissolved in 90 ml of H ₂ O water, after which 150 g of solid calcium hydroxide Ca (OH) ₂ is added to the resulting solution. The mixture is thoroughly mixed. The resulting aqueous dispersion has a paste consistency. The resulting aqueous dispersion in the form of a paste is applied to a double layer of 14x35 cm glass paper (BMD-F, density 11.2 g / cm ² , TU 6-11-529-80 or BMD-K, TU 6-48-93-92) a thickness of 1.5-2 mm and on top lay another layer of glass paper brand BMD-F or BMD-K. The resulting structure (composition) is rolled with rolls.

The molded adsorbent sheet is dried in a conventional laboratory or industrial control cabinet with air ventilation at a temperature of 100-140 ° C for 20-30 minutes. The resulting adsorbent contains 15 - 17% residual moisture.

Example 2

An aqueous dispersion is prepared, for which 12 g of sodium hydroxide NaOH are dissolved in 100 ml of H ₂ O water, after which they are added to the resulting solution

120 g of solid calcium hydroxide Ca (OH) ₂ and 30 g of magnesium hydroxide Mg (OH) ₂ . The mixture is thoroughly mixed. The resulting aqueous dispersion has a paste consistency. The obtained aqueous dispersion in the form of a paste 1.5-2 mm thick is applied to a layer of fabric Nomekh with a size of 14x45 cm and a layer of glass paper of the BMD-K or BMD-F brand is laid on top. The resulting structure (composition) is rolled with rolls.

The formed adsorbent sheet is dried in a conventional laboratory or industrial control cabinet with air ventilation at a temperature of 100-14O ⁰ C for 20-30 minutes. The resulting adsorbent contains 15-17% of residual moisture. Example 3

An aqueous dispersion is prepared, for which 7.5 g of potassium hydroxide KOH is dissolved in 90 ml of H ₂ O water, after which 100 g of solid calcium hydroxide Ca (OH) ₂ and 50 g of solid magnesium hydroxide Mg (OH) ₂ are added to the resulting solution. The mixture is thoroughly mixed. The resulting aqueous dispersion has a paste consistency. On a double layer of glass paper measuring 12x30 cm (BMD-F, density 11.2 g / cm ² , TU 6-11-529-80 or BMD-K, TU 6-48-93-92) with a thickness of 1.5-2 mm the resulting aqueous dispersion is applied in the form of a paste, and a thin layer of glass mat MCTB-2 TU 21-6328981-03-92 manufactured by Ivosteklo OJSC is laid on top. The resulting structure (composition) is rolled with rolls.

The molded adsorbent sheet is dried in a conventional laboratory or industrial control cabinet with air ventilation at a temperature of 100 - 140 ° C for 20-30 minutes. The resulting adsorbent contains approximately 15 - 17% residual moisture.

Example 4

An aqueous dispersion is prepared, for which 7.5 g of potassium hydroxide NaOH is dissolved in 100 ml of H ₂ O water, after which 75 g of solid calcium hydroxide Ca (OH) ₂ and 10 g of solid lithium hydroxide LiOH are added to the resulting solution. The mixture is thoroughly mixed. The resulting aqueous dispersion has a suspension consistency. The resulting aqueous dispersion is applied to a Rusar fabric layer measuring 14x35 cm in the form of a suspension 1.5-2 mm thick and one layer of glass paper of the BMD-F or BMD-K brand is laid on top. The resulting structure (composition) is rolled with rolls.

The formed adsorbent sheet is dried in a conventional laboratory or industrial control cabinet with air ventilation at a temperature of 100-140 ° C for 15-25 minutes. The resulting adsorbent contains 16 to 18% residual moisture.

Example 5

An aqueous dispersion is prepared, for which 9 g of potassium hydroxide KOH is dissolved in 100 ml of H ₂ O water, after which 70 g of solid calcium hydroxide Ca (OH) ₂ and 10 g of solid lithium hydroxide LiOH are added to the resulting solution. The mixture is thoroughly mixed. The resulting aqueous dispersion has a suspension consistency. The resulting aqueous dispersion is applied to a 16x30 cm Arcelon fabric layer in the form of a suspension 1.5–2 mm thick and a thin layer of glass mat MCTB-2 TU 21-6328981-03-92 manufactured by Ivotsteklo OJSC is laid on top. Received structure (composition) is rolled by rolls.

The formed adsorbent sheet is dried in a conventional laboratory or industrial control cabinet with air ventilation at a temperature of 100-140 ° C for 15-20 minutes. The resulting adsorbent contains 20 to 22% residual moisture.

Example 6

An aqueous dispersion is prepared, for which 15 g of potassium hydroxide KOH and 20 g of sodium hydroxide NaOH are dissolved in 100 ml of water H ₂ O. The mixture is thoroughly mixed. The resulting aqueous dispersion is a solution. The resulting aqueous dispersion in the form of a solution is applied to a layer of glass mat 2-3 mm thick. The resulting structure (composition) is rolled with rolls.

The reactivity of the adsorbent to carbon dioxide was assessed on a dynamic installation by determining the dynamic activity characterizing the ability of the adsorbent to absorb carbon dioxide from the gas-air mixture flowing through it and expressed in units of l / kg (the number of liters of absorbed carbon dioxide per 1 kg of adsorbent).

Adsorbent tests were carried out under the following conditions:

- diameter of the dynamic tube - 39 ± 0.5 mm;

- the cross-sectional area of the dynamic tube is 11.6 ÷ 12.25 cm;

- the height of the dynamic tube is 22 cm;

- the height of the adsorbent layer in the tube is 14 cm;

- the volumetric velocity of the air supplied to the tube is 6.72 ÷ 7.05 l / min;

- the volumetric rate of carbon dioxide (corresponding to its concentration in a gas-air mixture of 4% by volume) is 0.28 ÷ 0.29 l / min;

- the volumetric velocity of the gas-air mixture is 7.0 ÷ 7.35 l / min;

- the specific velocity of the gas-air mixture is 0.6 l / cm ² min;

- the temperature of the gas-air mixture is 23 ± 0.5 ° C;

- the relative humidity of the gas-air mixture at a temperature of 23 ± 0.5 ° C - 93 - 98%.

- the mass of the adsorbent in the dynamic tube is 110-140 g. Tests of the adsorbent were carried out until the concentration in the gas-air mixture behind the adsorbent layer was 3.0% of carbon dioxide.

Under similar conditions, comparative tests of the adsorbent made according to US patent N ° 5165399 were carried out.

The test results are presented in the table.

Table

As can be seen from the presented data, the claimed invention allows to increase the reactivity of the adsorbent by 20-40%, which expands the possibility of its use in air purification systems from carbon dioxide, while the method of manufacturing the adsorbent is technologically simple.

Claims

CLAIM

1 A method of manufacturing a carbon dioxide adsorbent for respiratory systems, comprising combining alkali and / or alkaline earth metal hydroxides with fibrous material, forming the absorbent in sheet form and drying, characterized in that the alkali and / or alkaline earth metal hydroxides are used as an aqueous dispersion, and the compound hydroxide of an alkali and / or alkaline earth metal with fibrous material is carried out by placing an aqueous dispersion between the layers of porous fibrous material.

2 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that the forming of the absorbent in the form of a sheet is carried out by rolling between the rollers.

3 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that a porous fibrous woven or non-woven alkali-resistant material with a low specific gravity is used as the fibrous material.

4 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that sodium, potassium, lithium, calcium, magnesium hydroxides are used as alkali or alkaline earth metal hydroxides.

5 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that the aqueous dispersion is used in the form of a paste.

6 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that the aqueous dispersion is used as a suspension.

7 A method of manufacturing a carbon dioxide absorbent for respiratory systems according to claim 1, characterized in that the aqueous dispersion is used in the form of a solution.